Exercise 2. (a) Let z = a + bi, and express a cos(wt) + b sin(wt) in terms of z, z, elt, and e-it. (Hint: Express cos(wt) and sin(wt) in terms of elt and e-it) (b) In (a), you should have obtained two terms. Show the two terms are complex conjugates of each other. (c) In the chapter on complex numbers, we showed that for any complex number w the real part of w (written as Re[w]) can be expressed as: Re[w] = Use this fact to show that w+w 2 a cos (wt) + b sin(wt) = Re[z. et]. As a consequence of Exercise 2, we can treat real signals that are combinations of cosine and sine waves

Advanced Engineering Mathematics
10th Edition
ISBN:9780470458365
Author:Erwin Kreyszig
Publisher:Erwin Kreyszig
Chapter2: Second-order Linear Odes
Section: Chapter Questions
Problem 1RQ
icon
Related questions
Question

Please do Exercise 2 part A-C and please show step by step and explain. 

**Exercise 2:**

(a) Let \( z = a + bi \), and express \( a \cos(\omega t) + b \sin(\omega t) \) in terms of \( z, \bar{z}, e^{i \omega t}, \) and \( e^{-i \omega t} \). (Hint: Express \( \cos(\omega t) \) and \( \sin(\omega t) \) in terms of \( e^{i \omega t} \) and \( e^{-i \omega t} \).

(b) In (a), you should have obtained two terms. Show the two terms are complex conjugates of each other.

(c) In the chapter on complex numbers, we showed that for any complex number \( w \) the real part of \( w \) (written as Re[w]) can be expressed as:
\[
\text{Re}[w] = \frac{w + \bar{w}}{2}
\]

Use this fact to show that:
\[
a \cos(\omega t) + b \sin(\omega t) = \text{Re}[z \cdot e^{i \omega t}]
\]

As a consequence of Exercise 2, we can treat real signals that are combinations of cosine and sine waves as the real part of complex signals composed of complex exponentials. It turns out that this enables us to bring in the theory of complex numbers (in particular, complex roots of unity) to gain extremely useful insights into the nature of these signals.
Transcribed Image Text:**Exercise 2:** (a) Let \( z = a + bi \), and express \( a \cos(\omega t) + b \sin(\omega t) \) in terms of \( z, \bar{z}, e^{i \omega t}, \) and \( e^{-i \omega t} \). (Hint: Express \( \cos(\omega t) \) and \( \sin(\omega t) \) in terms of \( e^{i \omega t} \) and \( e^{-i \omega t} \). (b) In (a), you should have obtained two terms. Show the two terms are complex conjugates of each other. (c) In the chapter on complex numbers, we showed that for any complex number \( w \) the real part of \( w \) (written as Re[w]) can be expressed as: \[ \text{Re}[w] = \frac{w + \bar{w}}{2} \] Use this fact to show that: \[ a \cos(\omega t) + b \sin(\omega t) = \text{Re}[z \cdot e^{i \omega t}] \] As a consequence of Exercise 2, we can treat real signals that are combinations of cosine and sine waves as the real part of complex signals composed of complex exponentials. It turns out that this enables us to bring in the theory of complex numbers (in particular, complex roots of unity) to gain extremely useful insights into the nature of these signals.
Expert Solution
Step by step solution of (a) : Find a,b,cos(wt),sin(wt)

Advanced Math homework question answer, step 1, image 1

steps

Step by step

Solved in 4 steps with 4 images

Blurred answer
Recommended textbooks for you
Advanced Engineering Mathematics
Advanced Engineering Mathematics
Advanced Math
ISBN:
9780470458365
Author:
Erwin Kreyszig
Publisher:
Wiley, John & Sons, Incorporated
Numerical Methods for Engineers
Numerical Methods for Engineers
Advanced Math
ISBN:
9780073397924
Author:
Steven C. Chapra Dr., Raymond P. Canale
Publisher:
McGraw-Hill Education
Introductory Mathematics for Engineering Applicat…
Introductory Mathematics for Engineering Applicat…
Advanced Math
ISBN:
9781118141809
Author:
Nathan Klingbeil
Publisher:
WILEY
Mathematics For Machine Technology
Mathematics For Machine Technology
Advanced Math
ISBN:
9781337798310
Author:
Peterson, John.
Publisher:
Cengage Learning,
Basic Technical Mathematics
Basic Technical Mathematics
Advanced Math
ISBN:
9780134437705
Author:
Washington
Publisher:
PEARSON
Topology
Topology
Advanced Math
ISBN:
9780134689517
Author:
Munkres, James R.
Publisher:
Pearson,